Contact-free Measurement of Heart Rate Variability via a Microwave Sensor

Measures of heart rate variability (HRV) are widely used to assess autonomic nervous system (ANS) function. HRV can be recorded via electrocardiography (ECG), which is both non-invasive and widely available. However, ECG needs three electrodes touching the body of the subjects, which makes them feel nervous and uncomfortable, thus potentially affecting the recording. Contact-free detection of the heartbeat via a microwave sensor constitutes another means of determining the timing of cardiac cycles by continuous monitoring of mechanical contraction of the heart. This technique can measure the heartbeat without any electrodes touching human body and penetrate the clothes at some distances, which in some instances may prove a practical basis for HRV analysis. Comparison of 5-minute recordings demonstrated that there were no significant differences in the temporal, frequency domains and in non-linear dynamic analysis of HRV measures derived from heartbeat and ECG, which suggested this technique may prove a practical alternative to ECG for HRV analysis

Wearable devices for health remote monitor system

It is feasible to see how communication and information technology have advanced at a rapid pace in today’s world. The introduction and emergence of wearable technology is one aspect that contributes to this advancement and has the potential to be an innovative solution to healthcare challenges, since it may be used for illness prevention and maintenance, such as physical monitoring, as well as patient management. To address some of the healthcare challenges, this research thesis provides a research methodology, research questions, and hypotheses for constructing an health remote monitoring system with alerts and continuous monitoring employing wearable devices capable of collecting biometric data on human health. The concept was then proven by the development of a prototype using wearable devices connected to a microcontroller, which transmits its data via MQTT Protocol to a Node-RED powered dashboard that handles health metrics monitoring and where all monitoring performed, and alarms generated can be viewed in real-time. All this data is delivered to a MongoDB database for further analysis and visualization. To demonstrate the effectiveness and capabilities of this prototype, it was used in the real world and the results were acquired from two distinct users. The results were very favorable and conclusive, demonstrating that the created prototype was satisfactory in providing data to support the developed hypotheses and research questions.É possível observar como as tecnologias de comunicação e informação avançaram a um ritmo bastante acelerado nos dias de hoje. A introdução e aparecimento da tecnologia ”wearable” representa um aspeto que contribui para este progresso e tem o potencial de ser uma solução inovadora para os desafios dos cuidados de saúde, uma vez que pode ser utilizada para a prevenção e manutenção de doenças, tais como a monitorização física, bem como para a gestão de pacientes. Para abordar alguns dos desafios dos cuidados de saúde, esta tese de investigação propõe uma metodologia de investigação, questões de investigação, e hipóteses para o desenvolvimento de um sistema inteligente de monitorização da saúde com alertas e monitorização contínua utilizando wearable devices capazes de recolher dados biométricos de seres humanos. O conceito foi então provado pelo desenvolvimento de um protótipo utilizando wearable devices conectados a um microcontrolador, que transmite os seus dados através do Protocolo MQTT a um painel de instrumentos alimentado por o Node-RED que lida com a monitorização de métricas de saúde e onde toda a monitorização executada, e os alarmes gerados, podem ser visualizados em tempo real e depois entregues numa base de dados MongoDB para posterior análise e visualização. Para demonstrar a eficácia deste protótipo, este foi implementado no mundo real onde foram adquiridos vários resultados através da utilização de dois utilizadores distintos. Os resultados foram bastante favoráveis e conclusivos, demonstrando que o protótipo criado foi satisfatório no fornecimento de dados para apoiar as hipóteses e questões de investigação desenvolvidas

HEART RATE MONITOR USING INFRARED

The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload,stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Thus,monitoring of heart rate plays a significant role in providing the status of cardiovascular system and clinically correlated information to medical professionals. Heart rate measurement is also regarded as an essential parameter in patient care monitoring system. Heart rate can be measured either by the ECG waveform or by sensing the pulse - the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be felt from those areas where the artery is close to the skin. This paper highlights on the design of a microcontroller (PIC series) based heart rate counter that is able to capture the pulse from finger tip by sensing the change in blood volume. The heart rates of fifteen healthy normal subjects (students of age 21-22 yrs.) both in relaxed and excited states were measured using the designed device and a standard heart rate measuring device. The outputs of the measured device were satisfactory. Also, the designed device,being noninvasive one, can easily find its place in health care monitoring system

Neuropathy Detection, Quality of Life Tools & Treatment for Type 2 Diabetes

Type 2 diabetes (T2D) mellitus has become the epidemic of the new millennium, with an estimated 382 million people affected worldwide as of 2013, and statistics projected towards 592 million by the year 2035. With the development of diabetes, complications have risen, with diabetic neuropathy becoming one of the most prevalent, affecting between 10–90% of those with the disease. Diabetic peripheral neuropathy (DPN) is difficult to detect in early stages of pathology, yet devastating once significant damage has taken place. Cardiac autonomic neuropathy (CAN), which is often silent, is associated with autonomic nervous system (ANS) dysfunction and increased risk for sudden death. Therefore, the purposes of this dissertation were early detection, assessment of quality of life (QOL) and disease intervention. Study I explored the effectiveness of the 128-Hz tuning fork, the 1-g and 10-g monofilaments, and the QOL-DN as tools for the early detection of DPN in overweight, obese and inactive (OOI), prediabetes (PD), and type 2 diabetes (T2D) individuals. Study II compared three QOL assessments: the QOL-DN, the PN-QOL-97 and the NeuroQOL-28, in OOI, PD and T2D individuals. Study III involved the execution of a double blinded, placebo controlled exploration of melatonin as a potential intervention for the improvement of ANS and sleep dysfunction in T2D. The results of Study I suggest that the 1-g monofilament and QOL-DN measures correlate to NC-Stat DPN Check portable nerve conduction study (NCS) findings, that these measures function well for early detection purposes, and that the 128-Hz tuning fork is a useful screening tool in OOI, PD and T2D populations, despite lack of correlation to NCS measures. The results of Study II suggest that the QOL-DN and the NeuroQOl-28 QOL instruments significantly predict NCS results, indicating that these measures are useful for screening and accurately assessing neuropathy within our populations of interest. Study III results indicate that a 10 mg dose of melatonin taken 30 minutes prior to bedtime for four weeks has a positive effect on PSQI Subjective Sleep Quality, systolic blood pressure (SBP) in deep breathing and Valsalva maneuvers, and HRV SDNN measures in individuals with T2D

Analysis of Wireless Body-Centric Medical Sensors for Remote Healthcare

Aquesta tesi aborda el problema de trobar solucions confortables, de baixa potència i sense fils per aplicacions mèdiques. La tesi tracta els avantatges i les limitacions de tres tecnologies de comunicació diferents per la mesura de paràmetres del cos i mètodes per redissenyar sensors per avaluacions òptimes centrades en el cos. La tecnologia RFID es considera una de les solucions més influents per superar el problema del consum d'energia limitat, a causa de la presència de molts sensors connectats. També s'ha estudiat la tecnologia Bluetooth de baixa energia per resoldre els problemes de seguretat i la distància de lectura que, en general, representen el coll d'ampolla de RFID pels sensors de cos. Els dispositius analògics poden reduir dràsticament les necessitats d'energia a causa dels sensors i les comunicacions, considerant pocs elements i un mètode de transmissió simple. S'estudia un mètode de comunicació completament passiu, basat en FSS, que permet una distància de lectura raonable amb capacitats de detecció precises i confiables, que s'ha discutit en aquesta tesi. L'objectiu d'aquesta tesi és investigar múltiples tecnologies sense fils per dispositius portàtils per identificar solucions adequades per aplicacions particulars en el camp mèdic. El primer objectiu és demostrar la facilitat d'ús de les tecnologies econòmiques sense bateria com un indicador útil de paràmetres fisiopatològics mitjançant la investigació de les propietats de les etiquetes RFID. A més a més, s'ha abordat un aspecte més complex respecte a l'ús de petits components passius com sensors sense fils per trastorns del son. Per últim, un altre objectiu de la tesi és el desenvolupament d'un sistema completament autònom que utilitzi tecnologia BLE per obtenir propietats avançades mantenint baix tant el consum com el preuEsta tesis aborda el problema de encontrar soluciones confortables, inalámbricas y de baja potencia para aplicaciones médicas. La tesis discute las ventajas y limitaciones de tres tecnologías de comunicación diferentes para la medición en el cuerpo y los métodos para elegir y remodelar los sensores para evaluaciones óptimas centradas en el cuerpo. La tecnología RFID se considera una de las soluciones más influyentes para superar el consumo de energía limitado debido a la presencia de muchos sensores conectados. Además, la baja energía de Bluetooth se ha estudiado se ha estudiado la tecnologia Bluetooth de baja energia para resolver los problemas de seguridad y la distancia de lectura que, en general, representan el cuello de botella de la RFID para los sensores de cuerpo. Los dispositivos analógicos pueden reducir drásticamente las necesidades de energía debido a los sensores y las comunicaciones, considerando pocos elementos y un método de transmisión simple. Se estudia un método de comunicación completamente pasivo, basado en FSS, que permite una distancia de lectura razonable con capacidades de detección precisas y confiables, que se ha discutido en esta tesis. El objetivo de esta tesis es investigar múltiples tecnologías inalámbricas para dispositivos portátiles para identificar soluciones adecuadas para aplicaciones particulares en campos médicos. El primer objetivo es demostrar la facilidad de uso de las tecnologías económicas sin batería como un indicador útil de dichos parámetros fisiopatológicos mediante la investigación de las propiedades de las etiquetas RFID. Además, se ha abordado un aspecto más complejo con respecto al uso de pequeños componentes pasivos como sensores inalámbricos para enfermedades del sueño. Por último, un resultado de la tesis es desarrollar un sistema completamente autónomo que utilice la tecnología BLE para obtener propiedades avanzadas que mantengan la baja potencia y un precio bajo.This thesis addresses the problem of comfortable, low powered and, wireless solutions for specific body-worn sensing. The thesis discusses advantages and limitations of three different communication technologies for on body measurement and investigate methods to reshape sensors for optimum body-centric assessments. The RFID technology is considered one of the most influential solutions to overcome the limitated power consumption due to the presence of many sensors connected. Further, the Bluetooth low energy has been studied to solve security problems and reading distance that overall represent the bottleneck of the RFID for the body-worn sensors. Analog devices can drastically reduce the energy needs due to the sensors and the communications, considering few elements and a simple transmitting method. An entirely passive communication method, based on FSS is studied, enabling a reasonable reading distance with precise and reliable sensing capabilities, which has been discussed in this thesis. The objective of this thesis is to investigate multiple wireless technologies for wearable devices to identify suitable solutions for particular applications in medical fields. The first objective is to demonstrate the usability of the inexpensive battery-less technologies as a useful indicator of such a physio-pathological parameters by investigating the properties of the RFID tags. Furthermore, a more complex aspect regards the use of small passive components as wireless sensors for sleep diseases has been addressed. Lastly, an outcome of the thesis is to develop an entirely autonomous system using the BLE technology to obtain advanced properties keeping low power and a low price

Physiological Information Analysis Using Unobtrusive Sensors: BCG from Load-Cell Based Infants' Bed and ECG from Patch Electrode

학위논문 (박사)-- 서울대학교 대학원 : 바이오엔지니어링전공, 2016. 8. 박광석.The aging population, chronic diseases, and infectious diseases are major challenges for our current healthcare system. To address these unmet healthcare needs, especially for the early prediction and treatment of major diseases, acquiring physiological information of different types has emerged as a promising interdisciplinary research area. Unobtrusive sensing techniques are instrumental in constructing a routine health management system, because they can be incorporated in daily life without confining individuals or causing any discomfort. This dissertation is dedicated to summarizing our research on monitoring of cardiorespiratory activities by means of unobtrusive sensing methods. Ballistocardiography and electrocardiography, which record the activity of the cardiorespiratory system with respect to mechanical or electrical characteristics, are both being actively investigated as important physiological signal measurement that provide the information required to monitor human health states. This research was carried out to evaluate the feasibility of new application methods of unobtrusive sensing that not been investigated significantly in previous investigations. We also tried to incorporate improvement essential for bringing these technologies to practical use. Our first device is a non-confining system for monitoring the physiological information of infants using ballistocardiography technology. Techniques to observe continuous biological signals without confinement may be even more important for infants since they could be used effectively to detect respiratory distress and cardiac abnormalities. We also expect to find extensive applications in the field of sleep research for analyzing sleep efficiency and sleep patterns of infants. Specifically, the sleep of infants is closely related to their health, growth, and development. Children who experience abnormal sleep and activity rhythms during their early infantile period are more prone to developing sleep-related disorders in late childhood, which are also more difficult to overcome. Therefore, studying their sleep characteristics is extremely important. Although ballistocardiography technology seems to represent a possible solution to overcome the limitations of conventional physiological signal monitoring, most studies investigating the application of these methods have focused on adults, and few have been focused on infants. To verify the usefulness of ballistocardiogram (BCG)-based physiological measurement in infants, we describe a load-cell based signal monitoring bed and assess an algorithm to estimate heartbeat and respiratory information. Four infants participated in 13 experiments. As a reference signal, electrocardiogram (ECG) and respiration signals were simultaneously measured using a commercial device. The proposed automatic algorithm then selected the optimal sensor from which to estimate the heartbeat and respiratory information. The results from the load-cell sensor signals were compared with those of the reference signals, and the heartbeat and respiratory information were found to have average performance errors of 2.55% and 2.66%, respectively. We believe that our experimental results verify the feasibility of BCG-based measurements in infants. Next, we developed a small, light, ECG monitoring device with enhanced portability and wearability, with software that contains a peak detection algorithm for analyzing heart rate variability (HRV). A mobile ECG monitoring system, which can assess an individuals condition efficiently during daily life activities, could be beneficial for management of their health care. A portable ECG monitoring patch with a minimized electrode array pad, easily attached to a persons chest, was developed. To validate the devices performance and efficacy, signal quality analysis in terms of robustness under motion, and HRV results obtained under stressful conditions were assessed by comparing the developed device with a commercially available ECG device. The R-peak detection results obtained with the device exhibited a sensitivity of 99.29%, a positive predictive value of 100.00%, and an error of 0.71%. The device also exhibited less motional noise than conventional ECG recording, being stable up to a walking speed of 5 km/h. When applied to mental stress analysis, the device evaluated the variation in HRV parameters in the same way as a reference ECG signal, with very little difference. Thus, our portable ECG device with its integrated minimized electrode patch carries promise as a form of ECG measurement technology that can be used for daily health monitoring. There is currently an increased demand for continuous health monitoring systems with unobtrusive sensors. All of the experimental results in this dissertation verify the feasibility of our unobtrusive cardiorespiratory activity monitoring system. We believe that the proposed device and algorithm presented here are essential prerequisites toward substantiating the utility of unobtrusive physiological measurements. We also expect this system can help users better understand their state of health and provide physicians with more reliable data for objective diagnosis.Chapter 1. Introduction 1 1.1. Cardiorespiratory signal and its related physiological information 2 1.1.1. Electrocardiogram 2 1.1.2. Ballistocardiogram 3 1.1.3. Respiration 4 1.1.4. Heart rate and breathing rate 5 1.1.5. Variability analysis of heart and respiratory rate 5 1.2. Unobtrusive sensing methods for continuous physiological monitoring 6 1.3. Outline of the dissertation 9 Chapter 2. Development of sensor device for unobtrusive physiological signal measurement 13 2.1. Unobtrusive BCG measurement device for infants health monitoring 13 2.1.1. Specifications of the device 17 2.1.2. Signal processing in hardware 18 2.1.3. Performance of the device 21 2.2. Unobtrusive ECG measurement device for health monitoring in daily life 25 2.2.1. Specifications of the device 26 2.2.2. Signal processing in hardware 28 2.2.3. Performance of the device 30 Chapter 3. Development of algorithm for physiological information analysis from unobtrusively measured signal 35 3.1. Algorithm for automatically analyzing unobtrusively measured BCG signal 35 3.1.1. Process flow of the algorithm 36 3.1.2. Performance evaluation 47 3.2. Algorithm for automatically analyzing unobtrusively measured ECG signal 57 3.2.1. Process flow of the algorithm 57 3.2.2. Performance evaluation 60 3.3. HRV analysis for processing unobtrusively measured signals 63 3.3.1. Optimum HRV algorithm selection in data missing simulation 64 3.3.2. Stress assessment using HRV parameters 67 Chapter 4. Discussion 71 Chapter 5. Conclusion 79 Reference 81 Abstract in Korean 89 Appendix 93Docto

Correlates of Vitamin D Status in Healthy Older Adults Living in Miami-Dade and its Association with Non-Skeletal Outcomes: A Cross-Sectional Study

Examining factors that affect vitamin D status in the fast-growing elderly population of Miami-Dade, Florida, is needed. Vitamin D deficiency in older adults has been linked to correlates of disability, including falls and fractures, and cardiovascular disease. The purpose of this study was to determine the proportion of vitamin D insufficient individuals and their relationship with vitamin D insufficiency in older adults (n=97) living in Miami-Dade. We evaluated the association between vitamin D status and 1) dual task physical performance to understand the link between vitamin D and cognition in the context of mobility; and 2) cardiometabolic risk, measured by galvanic skin response, pulse oximetry, and blood pressure to create a composite score based on autonomic nervous system and endothelial function. Participants completed baseline assessments that included serum levels of vitamin D, anthropometrics, body composition, dual task physical performance and cardiometabolic risk. Surveys to evaluate vitamin D intake, sun exposure, physical activity, and depressive symptoms were completed. Spearman’s correlations, independent t-tests, paired t-tests, repeated measures ANOVAs, and multiple logistic and linear regressions were used to examine the relationship of vitamin D insufficiency (25(OH)D /ml) and sufficiency (25(OH)D ≥30 ng/ml) with determinants of vitamin D status, dual task physical performance variables and cardiometabolic risk scores. Although the proportion of vitamin D insufficient individuals was lower when compared to the prevalance of the general United States elderly population, it was still common in healthy community-dwelling older adults living in Miami-Dade County, especially among Hispanics. Factors that affected skin synthesis (ethnicity, and sun exposure), and bioavailability/metabolism (obesity) were significant predictors of vitamin D status. Vitamin D insufficiency was not significantly correlated with worse dual task physical performance; however, cognitive performance was worse in the vitamin D insufficient group. Our results suggest a relationship of vitamin D insufficiency with executive dysfunction, and support an association with cardiometabolic risk using an innovative electro-sensor complex, possibly by modulating autonomic nervous system activity and vascular function, thus affecting cardiac performance

Can heart rate variability biofeedback mitigate the negative consequences of a social comparison challenge?

The present study sought to explore the ability of a single session of heart rate variability biofeedback (HRV BF) to mitigate the negative responses to a social comparison challenge. One hundred and fourteen undergraduate females were randomly assigned to one of three conditions: high-HRV BF, low-HRV BF, and no-BF. Following a single 15-min BF session, whereby they followed their assigned instructional set, participants viewed fashion magazine images while instructed to compare themselves to the models based on appearance characteristics. Consistent with previous findings, the social comparison challenge increased negative mood and body dissatisfaction across the sample as a whole. The effect of the social comparison challenge on negative mood was moderated by dispositional body concerns, with those higher on this dimension experiencing greater negative mood after viewing the images. In addition, time spent engaged in social comparison processing was related to more negative responses. The main finding indicated that HRV BF was not effective in reducing negative reactions for the average participant; however, resting HRV moderated the effectiveness of the intervention. Specifically, those with low intrinsic HRV benefitted the most from the HRV BF and experienced the least negative mood reactivity in response to the images. Results are discussed in terms of their relevance to the social comparison literature as well as to the future implementation and application of HRV BF